Pressure control valve



Sept. 4, 1945. c, y. s n- Y 2,384,202

PRESSURE CONTROL VALVE 7 Original Filed Feb. 24, 1941 2 Sheets-Shet 1 CONTROLL PRESSUR.

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Sept. 4, 1945. c. v. SMITH 2,384,202

PRESSURE CONTROL VALVE Original Filed Feb. 24, 1941 2 Shets-Sheet 2 I153. Fe

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99 85 66 7 CHARLES M SMITH,

. wwyflm T Patented Sept. 4, 1945 PRESSURE CONTROL VALVE Charles v. Smith, Dayton, Ohio, assignor to The Univis Lens Company,

tion of Ohio Dayton, Ohio, a corpora- Original application February 24, 1941, Serial No. 380,149. Divided and this application October 1, 1941, Serial No. 413,189

8 Claims.

This invention relates to an apparatus for controlling the operation of a forming press for shaping a mass of synthetic resin, and more particularly, relates to a pressure control for accurately controlling the supply of a pressure fluid to the forming press.

When producing optical articles from a solidifled mass of plastic material, it is necessary that the original properties of the material be retained. There are certain synthetic plastic materials, such as Plexiglas, Lucite, Crystallite'and others, which are organic resins produced by the polymerization of the monomeric derivatives of acrylic and methacrylic acids, which are acceptable for use in forming optical articles such as lenses, and more particularly ophthalmic lenses.

In order to produce high grade optical articles from synthetic plastic materials it is necessary that the various steps in forming or shaping the article by the pressing method shall be accomplished under accurate control. It is also required that the pressing or deforming of a blank or mass of plastic material shall not be carried out at too great a rate of deformation. If-a mass of resinous material is formed into 'a lens, and the forming is carried out at too rapid a rate, there is an internal disorder which produces an internal stress which alters the index of'refraction of the material thereby displacing the optical paths through the same. These strains can be termed optical strains since they'are of insufficient value to cause any mechanical difiiculty in the material and are imperceptible to the eye. They are-only noticeable when the material is used as a lens, the optical path displacement showing up very definitely under such conditions.

It is therefore anobject'of this invention to provide a pressure regulating device for accurately controlling the flow of fluid pressure to the press for operating the same. I V

It is another object of the invention to provide a pressure regulating apparatus having a me chanical actuator which is associated with a compound lever system which reduces the effective movement of the mechanical actuator in a manner that a valve mechanism controlled thereby is provided with a relatively small movement in comparison to the movement of the mechanical actuator.

It is another object of the invention to provide a pressure regulating valve for accurately controlling an increasing pressure which is supplied to a pressure operated mechanism, such as a ress. 7

It is another object of the invention to pro-- vide a pressure controlling device which will accurately establish and hold pressure once established, the valve permitting an increase of the pressure supplied therethrough and constructed and arranged for holding the new pressure established. a

It is another object of the invention to provide a pressure regulating 'valve for accurately controlling the supply of fluid pressure to apressure actuated device wherein the controlling mechanism will either supply fluid to'the device or exhaust fluid therefrom to permit a balance of pressure against a resilient pressure determining device, thereby establishing an accurately controlled pressure in thefluid pressure actuated mechanism. 3 r

It is anotherobject of theinvention to provide a pressure regulating valve for accurately actuating the platens of a press and for controlling the pressure applied thereby upon an article 'formed between the platens. p 7

It is another objectof the invention to provide a time controlled pressure control regulating mechanism for accurately controlling the pressure applied to the pressure mechanism of a formingpress. I Further objects and advantages'will be apparent from the drawings and the following description This application is a'division of my copending application, Serial No. 380,149, filed February 24, 1941. j

Inthedrawings:.

Figure 1 is a diagrammatic view/of a press and operating system associated therewith' for performing the operation of this invention.

Figure 2 is a cross-sectional'view of ,a' pair of forming dies adapted to 'be'associated'with the forming press for producing a lens. Y Y

Figure 3 isiajcross sectionalview, of a somewhat diagrammatic showing of apressure regulating valve for controlling pressure applied to the forming press.

Figure 4 is a cross section'al'view takenalong line 4-4 "of Figure 3 showing the control valve of the pressure regulating device in the closed position.

' Figure 5 is a similar view of the valve of Figure 4 but arranged in the open position. I

Figure 6 is a view similar 'to Figure 4, butshow ing thevalve in the position, for bleeding pressure fromthe pressure operating mechanism of the press. f: I ,In the manufacture of ophthalmic images, or any other lens which is to be a true optical ar- 'This applicant has found that when a sheet of resin is altered in its configuration that unless the rate of movement of the sheet is controlled during the forming thereof'thattheoriginal index of refraction is altered, andth-atthis alteration is not uniform throughout the mass of the article, thereby resulting in a, bi-refringent.

optical article.

The resin is formed between suitable die sur V faces which are moved toward one another by a, suitable forming press. The rate of movement of the; die surfaces thus. controls the rate or moyement of the resin. Therefore, it is essential that the fiuidflow to the p ss r c u t e the same shall he accurately controlled at a predetermined rate and the pressure shall be accurately governed to prevent any undue increase of pressure during the forming process.

The pressurereg-ulating valve of this invention. constructed; and arranged in a manner that a. very fine and accurate control over the pressure in the fl uidz conduit to. the press is obtained. The valve is adapted to either supply fluid tov the press-or to permit fluid to discharge 7 from the press to establish an accurate pressure therein which is, controlled by means of a balancing spring. The forming press and system associatedtherewith discl sed in thi ppl tion is. particularly adapted to the manufacture of plastic lenses. 1 v

V The forming press consists, of a platen, 10. car ried upon a stationary head ll, and a platen, I2, carried;- upon a. movable head [3, which head I3; is carried by a. pillar L4. The pillar i4 is journaled in the bearings. 15: which are secured by meanso'f. the bolts. l6. to the stationarysupport, ll. The head I3 is carried upon the upper end of the. pillar l4 while the lower end thereof is connected to. a. diaphragm. motor IS. The diaphragm motor [8 is connected to a source of fluid pressure, such as the fluid reservoir l9, by means of the conduits 20 and 2|. A manually controlle'ds way valve 22 is positioned in the conduit 20 for controlling the flow of fluid pressure from thefluid storage tank [9 to. the diaphragm motor-l8. The valve Zlcan be operated. to permit the. flow, of fluid pressure to. the motor [8, or can exhaust the pressure from the motor [8. by way of. the exhaust conduit 23...

A fluid pressure regulating. or c ntrol valve 26. is positioned in the conduit 20' and is located between the. fluid pressure'storage tank I9 and, the hand operated valve 22.. This pressure control valve 24 is operated to gradually increase the pressure upon the diaphragm motor I8 for: ex-

' pending the same and thus to close the platens press mechanism since the pressures involved,

platens l0 and l2 in any suitable manner but, as shown in Figure 2, the die halves can be carried within the recesses 2! and 28 provided in the platens'lfl and 12 respectively. Suitable means can be provided for removably positioning the die halves 25 and 2B in the recesses 2! and 28 respectively, to permit. ran-loyaland; insertion of various cooperating pairs' 'of die elements. As shown in Figure 2, the die halves 25 and 26 are provided with cooperating die surfaces 29 and 30 respectively which are of the desired surface curvature for producing a lens from a mass of resinous material: positioned therebetween, the surfaces being arranged to cooperate with one another to produce a lens having the desired surfacecurvature. The surfaces 29 and 39 of the die halves 25 and 26 are finished to the desired perfeotionwhich will impart a surface finish upon the mass of resinous material suitable for optical use.

The platen-s Ht and 1.2 are provided with passages suitable fer the circulation of a heating or a cooling fluid thereth-rough. To provide a source of fluid heat fercirculation through the passages in the platens Ill and $2 a steam boiler '3: is provided. This boiler can be heated by any suitable source of 'heatfor-maintaining; the steam loop 32 filled; with live; steam. It is of course to be understood that the steam boiler 3!. represents. any source or fluid-heat which canbe arranged for circulation through the passages provided in the platens. If} and t2 7 H A conduit 33-connects the upper portion of the steam loop 32. with the inlet conduits 34 and 3.5, connected to the platens. Ill. and [2 re.- spectively. A steam return conduit 36 is 0on nected to the platens l0 and 8.2 respectively by means of. the conduits 3.1 and 33f The conduit 35 connects with the: lower portion of the steam loop. 3.2 forreturn of condensed steam to the steam boiler 3L, While the. presentdes p n refers tosteam as. the heating fluid for circus lation through the platens of the press, it can readily be understood that 1 any other fluid can be used for circulation through the plate ens for heating the same. to any desired temperature. The, steamloiopl 32 provides, means whereby steam at a constant temperature is available. for circulationthrough ;theconduits 3.3., 3, 1v and 3.5, and will be" 01 av more even. tam perature than if, the conduit, connecting-the steam source with; the conducting conduits. 3,3, 3.4 and 35 would be a dead end conduit.

To control, the circulation of the. steam through theconduits 3,3. and. 3.6. shut-oil valves 33 and 411 respectively are placed in. the conduits. These fluid flow control valves39. and snare ope ated by means of. the. diaphra m. motored I. and 42. respectiv ly. The. motors 4L and, 42.: aref'connected by means of the conduits 43 and'flpdj re spectively to the conduit). E5.., which latter con-- uit is connec d w th the, conduit zlileadi g rom h flu d p ess ource. HI- .A 3-W y solenoid valve is positioned' 'the conduit 45 between the pressure source [9; and the 'di'e aphragm motors 4| and 42. The solenoid; valve 46 when energized. is adapted to. open to permit fluid'pressure to pass from the conduit into the conduits 43 and M for operatingthe diaphragm motors 4| and 42. Whenthe'sol'enoid' An exhaust conduit 48' is connected to the.

conduit 33 and in which th is u e fluid flow control valve 49, which valve isnor mally closed when deenergized. Thevalve '49 provides means for exhausting pressure from the conduits 33, 34, 35 and 36 during a certain-portion of the cycle of operation of the formingpress, which will be hereinafter described.

During a certain portion of the cycle of operation of the forming press a cooling fluid is circulated through passages in the platens I and I2. The heating and cooling passages in the platens may be independent passages or can be a common set of passages. As disclosed in Figure: 1, both the heating and cooling medium circulates through the same set of passages. A conduit 50 connects the conduit 36 with a source of cooling fluid which is under pressure. A unidirectional fiow check valve is positioned in the conduit 50 and controls the flow of cooling fluid into the conduit 36. The checkvalve 5I is adapted to open for the passage of fluid in the direction of the arrow indicated adjacent the conduit .50, the check valve closing against return flow of fluid.

, The check valve 5I is adapted to be closed by the pressure of the heating fluid when heating fluid under pressure is present in the conduit 36,. the pressure of the heating fluid overcoming the pressure of the cooling fluid to close thecheck valve 5I and thus prevent circulation of cooling fluid through the conduit 36 as long as heating fluid is present therein and is under pressure. 1

To control the rate at which the pressure will be increased within the diaphragm motor I8, for moving the die half 26 against the die half .25, the valve or pressure regulator 24 is gradually opened to permit increasing pressure to pass therethrough into the conduit 20. The pressure regulating valve 24 is provided with an actuating arm 52 which engages a cam track 53 provided in a disk 53a mounted on the shaft of a timing motor 54. The shape of the cam track 53 is pre-designed to open the valve 24 and permit fluid pressure to pass therethrough at a predetermined rate of increase, which rate of increase has been predetermined to govern the rate of forming a mass of resinous material placed between the die halves 25 and 26. As

previously mentioned, the rate at which a mass at which the article is formed is governed also by the temperature of the article during the forming process. The rate of forming and the temperature at which the article is held during the forming is coordinated to produce a formed article which will be substantiallyfree of optical strain. To accomplish the given rate of formation the contour of the cam track 53 must be predesigned in order to open the valve 24 at the proper rate to permit passage of fluid pressure to the diaphragm motor I8 at the proper rate.

The pressure regulating valve 24 consists of a casing 38 within which there is secured a plunger valve 8i which controls the passage of air pressure, from the supply line 2| to the conduit which interconnects the valve 24 with the diaphragm motor I8. The plunger valve 8| has a lower body portion 82 and an upper body portion 83 which are secured together by means of the screws 84. The lower body portion 82 has-a horiprovided in the upper body portion 83.

zontal bore which extends partly through the body portion 82 and communicates .with a vertical bore 86. The vertical bore 86 communicates with a vertical bore 81 provided in the upper body portion 83. These bores 85, 86 and 81 provide the inlet passage communicating with the pressure conduit 2I. A similar horizontal bore 89 is provided in the lower valve body portion 82 which extends partially through the body and communicates with a vertical bore 90. The vertical bore communicates with a vertical bore 9| The bores-89, 90" and SI provide the discharge passage from the valve 8| connectingwith the discharge conduit 20. i

A bore 92 extends horizontally through the upper body portion 83 and forms the cylinder within which a plunger or piston 93 is adapted to reciprocate. The plunger 93 has an end portion which fits the bore 92, which end portion 94 is separated from an annular collar portion 95 by means of an annular undercut portion 96. The annular collar portion '95 is separated from an end portion 91 by means of'an annular undercut portion 98. .The portions 94, 95 and'9I are of equal diameter for engaging thebore 92-in a piston-like relation. A leaf spring 99 urges the plunger 93 in a left-ward direction, asviewed in Figures 4, 5 and 6.

A mechanism for actuating the plunger 93 in response to the pressure within the diaphragm motor I8 consists of a Sylphon bellows I00 which hasv one end thereof secured to a stationary mounting member IOI, which member is secured to the casing 80 by means of the screws or bolts I02. The opposite end of the Sylphon I00 is engaged by a compression spring I03 which has one end thereof in engagement with the closure member I04 of the Sylphon, and the opposite end thereof in engagement with an adjusting collar I05. The collar I05 is threaded upon a stationarily 'mounted stud I06 for altering the degree of compression of the spring I03. A conduit I0! is secured to the mounting II and communicates with the interior of the Sylphon' I00. The opposite end of the conduit I0I communicates with the discharge conduit 20 from the valve member 8| and thus conducts the pressure from the discharge conduit 20 to within the Sylphon The Sylphon bellows I00 actuates the plunger 93 through means of a lever arm I08, which is loosely carried upon a pin I 08a secured to the end portion I04 of the Sylphon bellows; The pin I08a thus becomes a pivot for the loosely mounted lever arm I08. The opposite end of the lever arm I08 engages a lever arm I09 and is connectedthereto by means of the pivot pin H0. The lever arm I09 has an extending ear III to which there is connected one end of the tension spring H2, the opposite end of the tension spring being secured to the pin H3 fastened in the body of the casing 80.

The plunger 93 has a stem portion II4 which extends into engagement with a cup member H5 by means of a pivot pin II]. The lever arm I I5 is pivotally carried upon a wall of, the casing 8.5: by m ans of. he pivot pin H8, The arm; H16 engages the arm I89 through means of an actuating'pin H9, which pin is adjustably; carried upon the arm H5; for longitudinal adjustment thereupon to vary the leverage between the arm hand the arm I05.

The regulating valve 24 just, described provides a very accurate control mechanism for regu1at-- ins the pressure applied to the diaphragm motor I8, When the cam disk 53a is driven by the timing motor 54, the actuating, arm 52 will be moved in a rightward direction, as viewed in Figure 3, whereby the arm H6 will b pivoted about the. pivot point IIBto permit the lever arm I08 to be moved in a rightward direction about the fulcrum pin 108a by means of the spring I i2. This move-v mentis accomplished through the pivotpin III) which interconnects the lever I09 with the lever arm I08. -Movement of the lever arm L09 by means of the actuating arm 52 permits a corresponding movement of the lever arm IllBz, When the lever arm I08. is moved ina rightward direction, as viewed in Figure 3, the plunger extension I IA, actuates the plunger93 in a rightward direction whereby the collar 95 opens the bore -81: to the annular space- 93 around the plunger 93, and thus air pressure from the conduit H can pass from the bore 81 tov the bore 9| to the conduit 29. Pressure in the conduit 211 will then be present inthe conduit I01 to apply pressure to the Sylphon bellows I00. According to the compression of the spring I03 the bellows I will be moved in a leftward direction to move the enld wall I04 thereof and thus the pin 38a, Movement of the pin I08a in a leftward direction permits the arm I08 to move in a leftward direction as fulcrumed about the pivot pinl II] whereby the plunger 93 is moved in a leftward direction by means of the leaf spring 99 to close the bore 8'! from communication with the bor 9|. The collar 95 on the plunger 93, is at this time between the bores 8'! and SI. 1

If the pressure increase in the conduit has been just sufficient to be balanced by the compression spring I93 the previous result will be obtained. However, if the pressure in the conduit 20 should exceed the compression forc for the spring I 03 the bellows I80 will expand in a leftward direction until the increased pressure is balanced against the compression force of the spring, under which'condition the lever arm I08; may have permitted sufi'icient movement of the plunger 93 in a leftward direction that the portion 9! of the plunger leaves the bore 92. Such a position is indicated in Figure 6. this position the bore 9| is open to the atmosphere through the port I20 provided by removal of the plunger portion 91 from the bore 92. Air can then escape from the conduit 20 through the bores 90 and 9i and the port I20 to the atmosphere and the pressure in the Sylphon bellows I00 is reduced to a point balanced by the spring valve 8| until the ivot pin 158a. mo s, lettward sufiiciently to. p rmith nnuler r'95. nith piston 93,: to close th ports 8 The p ine. H13 determines the degree of pressure increase which has o curred, Th ever system, hus prov des aimechanism whereby the movem nt. r he. act-11.- ating arm 52 is greatly reduced when transmitted to,- the piston 93 so that in effect, the piston 93 is moved with a micrometer adjustment and there.- byproviiding a very accurate pressure regulating controlling member for regulating the pressure. to

the, Sylphon I00.

As previously described, the cam track 531531 the disk 5.3a has a predetermined contour for gradu allymov-ing the-actuating arm 52 in a rightward direction, as viewed in Figure 3, whereby: an ins creasing pressure is required the bellows. I00 to offset the increased opening attempted to. be made by the cam disk 53a. This increase in pressure actuates the diaphragm motor I,8;to op;- erate' the forming press. 7 Since the contour of the cam track 53 is predetermined to produce. a predetermined rate of pressure increase Over a predetermined time interval, it can readily" be seen that the regulating valve 24 provides a. very accurate control over the pressure applied to the diaphragm motor I8. 7

' A microlimit switch 55 is positioned adjacent the platens I-0 and I2 and is adapted to be op erated by an arm 5.6 extending fromthe movable platen I2. The microlimit switch- 55, which is shown diagrammaticall-vin Figure I, consists ota leaf spring 51 which is rigidly mounted at one end thereof, as indicated at 58. The center portion of the leaf spring 51 is formed arcuately and is so arranged that when pressure is applied to the arcuate portion thereofthe spring 5 1 will snap over c'enterin the manner of the well known cricket spring. Thefree end of the leaf spring 51 carries a contact 59 which is adapted to engage a contact 60 when in one position or a con tact 6| when the opposite position. The device for operating the leaf spring 51 consists of a cup member 52' within which-there is mounted a, piston 63 carrying an extenlding rod 64, the piston 63 being slidabl'e within the cup shaped member 62. A spring 65 is positioned between the piston 63 and the cup shaped-member 62*. Th cup shaped member 62 isrsopositioned with respect to the press'platen I2, that the arm 56 can engage the cupped member 62 for moving the rod 64 into engagement with the arcuate portion of the leaf spring 51.

The microlimit switch 55 is. adjustably positioned with respect to the platens I0 and I2to permit the spaced relationshipfojf' the platens to be varied before the limit switch becomes effective. Since the limit switch is operated by a very slight movement, the switch becomes a means for accurately controlling the spaced relationship of the die halves 25v and 26, and thus determines the thickness of a lens formed therebetween.

The limit switch 55, controls concomitant operation of the timing motor 54, and the solenoid 46. An electric circuit is established for the timing motor 54 through the lines 66, 61 and 68, the contacts 60 and 59 and the line 69,, Atthe same time an electric circuit is established for the solenoid,

when the limit. switch 55. is in the position with the contacts 59, and 60 closed. A hand switch [2 is provided in the electric circuit for the timing motor 54.

When the limit switch 55 is in position with the contacts 59 and 6| closed electric circuit is established for the solenoid valve 49 through the lines I3, 14 and 69, the circuit at this time being broken through the solenoid valve 46 and the timing motor 54.

The cycle of operation for the press when forming an opticalarticle from a mass of resinous material, and particularly when forming lenses of a high degree of perfection is as follows. When starting a cycle of operation the press and the operating mechanism is as shown in Figure 1. At this time the solenoid valve 46 is open so that pressure from the fluid storage reservoir I9 is applied to the diaphragm motors 4| and 42, whereby the valves 39 and 40 are open. Steam from the boiler 3| is circulating through the conduits 33, 34 and 35 to the platens I and I2 respectively, the steam pressure is present in the conduits 31, 38 and 36, thus completing the steam circuit through the platens. The presence of steam pressure in the conduit 36 closes the check. valve 59 to prevent cooling fluid from entering the conduit 36, it being understood for this purpose that the steam pressure in the conduit 36 is above the pressure of the cooling fluid in the conduit 50. The check valve 5| @being of an ordinary swing type is closed by the differential of pressure on the two sides thereof.

The platens l0 and I2 are thus being heated as well as the die halves 25 and 26. It will be understood that at this time the manual control valve 22 has been turned to open the exhaust conduit 23 so that no pressure is existing in the diaphragm motor |8 whereby the die halves 25 and 26 are permitted to remain in'the open position as shown in Figure 1.

Sufiicient heating time is given the die halves 25 and 26 to bring them up to a desirable temperature after which a mass of resinous material is positioned upon the die half 26. If an ophthalmic lens is to be formed the'mass of resinous material can be in the form of a disk of suitable thickness, which can either be a flat disk or can be preformed to a slight extent with substantially the surface curvature of the die halves 25 and 26.

The cam 53 on the timing motor 54 is set manually so that the actuating arm 52 of the valve 24 will close the valve 24. The valve 22 may now be operated to close the exhaust conduit 23 and to open the through connection in the conduit 20 thereby establishing communication between the valve 24 and the diaphragm motor Hi. The hand switch 12 is now closed whereupon the timing motor 54 is started. Initial rotation of the cam opens the valve 24 slightly whereupon pressure from the fluid pressure reservoir I9 is conducted to the diaphragm motor I8. It will be understood, however, that at this time the pressure in the conduit 20 and the diaphragm motor I8 is just suflicient to close the die half 26 against the die half 25 and to place a very slight pressure upon the lens blank positioned therebetween. This initial pressure is retained within the diaphrgam motor for a predetermined interval of time, the time interval being determined by the rotation of the cam 53, the contour of the face oithe cam being shaped in such a manner that the initial position of the valve 24 is retained for whatever. determined period of time desired. During this period steam is circulating through the platens l6 and I2 whereby the lens blank, positioned between the die halves 25 and 26, is brought to a desirable molding or forming temperature.

After rotation of the cam through the predetermined interval of time, as determined by the timing motor 54, the contour of the cam 53 will then effect a gradual increase in the opening of the valve 24, whereby the pressure in the conduit 26 and the diaphragm motor |8 will gradually increase. The increasing pressure within the diaphragm motor It! will cause the die half 26 to move toward the die half 25 and thereby form the lens blank positioned therebetween to the configuration of the face surfaces 29 and 30 of the respective die halves. As previously mentioned the rate of this formation is determined by the contour of the cam 53 since the contour of this cam'determines the rate of opening of the valve 24 and thus the rate of pressure increase in the diaphragm motor l8.

Upon the die halves 25 and 26 reaching a predetermined spaced relationship, which spaced relationship determines the thickness of the lens formed therebetween, the arm 56. will engage the microlimit switch 55 to causethe leaf spring 51 to snap over center and break engagement with the contact 60 and make contact with contact 6|.

When electric circuit is broken through contacts 59 and 60 the timingmotor 54 and the solenoid valve 46 are deenergized, whereby the pressure in the diaphragm motor I8 is prevented from further increase since the valve 24 will not be open any further andiwill hold th pressure at this point. The solenoid valve 46 will close the through passage from the conduit and will open an exhaust passage 41 whereby the pressure in the diaphragm motors 4| and 42 will be released to the atmosphere, thereby closing the valves 39 and40. i At the instant electric circuit was broken through contacts 59 and 60, electric circuit was made between contacts 59 and 6| whereby the valve 49 was energized to open the exhaust conduit 48. When the exhaust conduit 48 is opened steam pressure existing in the conduits 3 3, 34, 35, 36, 31 and 38 is exhausted to the atmosphere. This release of pressure in these conduits, and particularly in conduit 36, permits the pressure of the cooling fluid in the conduit to open the check valve 5| andvpass therethrough into the conduit 36. from. the conduit 36 to the conduits 31 and.38 into the platens l0 and I2 respectively, and will discharge therefrom through the conduits 34 and 35 and the exhaust conduit 48.

The circulation of cooling fluid in this circuit is maintained until the valve 22 is manually operated to establish connection between the diaphragm motor I8 and the exhaust 23, whereupon pressure is released from the diaphragm motor to permit separation of the platen l2 from the platen [0. It will be understood that the cooling portion of the cycle of operation of the press is determined according to the experience of an operator who will know when it is time to open the die halves 25 and 26 for removal of a lens formed therein. a

When the platen |2 separates from the platen 10, the leaf spring 51, of, the microlimit switch 55, will snap to its normal position, as indicated in Figure 1, to reestablish electric circuit between the contacts 50 and'60. Reestablishment of this electric circuit again opens :the solenoid valve 46 whichin turnpermits pressure to be applied to the diaphragm motors 4| and 42 to reopen the The, cooling fluidv will then pass valves 38 and 40. Breaking of electric circuit between contacts 59 and 6.1 deenergized. the. sole.- noid 49 to close the exhaustv conduit 48- The heating circuit is thus reestablished to the; platens l and i2, the pressure then building up in the conduit 38 to close thecheck valve .and prevent the cooling fluid from entering the. conduit At the time the manually operated valve 22v is opened the hand switch 12 is. also opened so that the timing motor 54 is now inoperative for further actuation of the valve. 2%. The. press. is now in condition for the. beginning of the next cycle. of operation which can be repeated as previously described.

While the formand embodiment. herein described is.a preferred .form, yet it will-be understood that I. desireto comprehend Within. the

.scope of my invention all .modifications falling within the purview" of my invention.

Having thus fully describedmy invention, what I claim as new and. desireto secure. by Letters Patent is:

1. An apparatus for controlling the flow of pressure fluid to a forming press comprising pressure regulating valvemeans for opening. and closing a fluid conducting conduit, means actuated by the fluid pressureon the. discharge side of said valve for closing saidvalve, means for urging the said'actuated means toward valve closing position, and means opposing said last. mentioned means actuatedby a time controlled mechanism for gradually opening said valve to: increase the fluid pressure on the discharge side of said valve before the pressure actuated means can respond to close said valve. a r

2. An apparatus for controlling the flow of pressure fluid to a formingpress comprising pressure regulating valve means for opening and closing a fluid conducting conduit,.means actuated by the fluid pressure on the discharge side of said valve means for urgingv the same toward closed position, means opposing said last mentioned. means actuated by a time controlled mechanism for gradually opening said valve, and resilient means opposing said pressure actuated means to. adjust the operating pressure of said latter means.

3. A. pressure regulating valve comprising a piston valve, an inlet port and outlet ports for said valve, the piston of said valve comprising an annular'recess communicatable with said inlet port, a second annular recess communicatable with said outlet ports and an annular shoulder between said recesses, expansible means for receiving pressure fluid discharged from said valve, resilient means opposing movement of said expansible means, a lever having one end pivotally associated with said expansible means, means for actuating the free end of said lever, and means terconnecting said piston valve with said-lever e a point intermediate the pivot connection and the free end thereof.

4. A pressure regulating device for controlling the flow of pressure fluid to a forming press which includes, pressure actuated means, lever means having one end thereof engaged by said pressure actuated means, mechanically actuated means engaging the opposite end of said lever means for movement thereof, whereby said lever means floats between said pressure actuated means and said mechanically actuated means, valve means including a body having a. piston plunger therein that extendsfromsaid body into engagement with said lever means, inlet and discharge port so a means in said body for conducting pressure fluid to and from saidbody, annular recesses in said piston plunger for interconnecting said port means to conduct pressure fluid through said body and. for connecting the discharge port. means in said body with an exhaust, conduit means connecting the discharge port means in said body with said pressure actuated means for thereby moving said lever means to move said valve means to close the inlet port upon an increase in pressure on the discharge side of said valve means, said mechanically actuated means opposing movement of said lever means by said pressure actuated means to thereby urge said valve means to the open position, whereby said pressure actuated means and said mechanically actuated means produce a, balance for establishing a-predetermined pressure. on the discharge side of said valve means.

flow of pressure fluid to a forming press which includes, pressure actuated means, lever means engaging said pressure actuated means form'ovement thereby, mechanically actuated means engaging said lever means for opposing the movement of said lever by said pressure actuated means; valve means actuated by said lever means including a. body, piston valve means slidable within said body having one end thereof extending from said body, inlet and discharge port means in said body for establishing .a fluidflow passage through said body which includes the cylinder for said piston means, said piston valve means having annular recesses therein. for in.- terconnecting said port means through the cylinder of said piston. valve means and for connecting the discharge port with an exhaust through the cylinder for said piston valve means; and conduit means connecting the discharge port in said body with said pressure actuated means, whereby said valve means is actuatedto produce a predetermined pressure in the discharge port.

6, An apparatus for controlling the. flow of pressure fluid to a. forming. press comprising pressure regulating valve means constructed and arranged to pass pressure fluid from the. inlet to the outlet side thereof and to exhaust pressure fluid from the outlet side thereof, means. actuated by the fluid pressure on the discharge side of said valve means for urging the same toward closed position, and means opposing said last mentioned means actuated; by a time controlled mechanism for gradually. opening said valve to increase the fluid pressure on the discharge side of said valve before the pressure actuated means can respond tov close said valve, said pressure actuated means also actuating said valve to relieve pressure from the discharge side. of .said valve when the pressure. fluid added to the dis charge side of said valveoverbalances. the opening of said valve by said time controlled mechanism. g

'7. A pressure regulating device for controlling flow of pressure fluid toa formingpress 'comprising valve means adaptedto' be inserted in the pressure conduit connecting the forming press to a, source of pressuresaid valve meansincluding a body having a piston plunger thereincontrolling inlet port'means. discharge port means and exhaust port means in said body to regulate the flow of pressure fluid passing. through said body, said plungerhaving,anannular recess to interconnect said inlet port with said discharge port and said discharge'portv with said. exhaust selectively to openand close the same, lever 5. A'pressure regulating device for controlling means having both ends movably carried engaged by said plunger means which is actuated thereby, means actuated by pressure fluid discharged from said discharge port means operably connected to one end of said lever for moving said plunger means in one direction of movement, and means movable in opposition to said last mentioned means operably connected to the opposite end of said lever to move the same and thereby cause a movement of said plunger means which is the resultant of the movement of both ends of said lever means.

8. A pressure regulating device for controlling flow of pressure fluid to a forming press compresing valve means adapted to be inserted in the pressure conduit connecting the forming press to a source of pressure, said valve means including a, body having a piston plunger therein controlling inlet port means discharge port means and exhaust port means in said both? to regulate the flow of pressure fluid passing through said body, said plunger having an anmilar recess to interconnect said inlet port with said discharge port and said discharge port with said exhaust selectively to open and close the same, lever means having both ends movably carried engaged by said vplunger means which is actuated thereby, means actuated by pressure fluid discharged from said discharge port means operably connected to one end of said lever for moving said plunger means in one direction of movement, and means movable constantly in at least one direction of movement for a predetermined distance of movement in opposition to said last mentioned means operably connected to the opposite end of said lever to move the same continuously in the said one direction of movement and thereby cause a continuous movement of said plunger means in the said one direction which is the resultant of the movement of both ends of said lever means to cause a gradual pressure change in said discharge port.

CHARLES V. SNIITH. 

